Air pollution led to genetic changes that may have sapped learning skills in children whose mothers were exposed to a Chinese coal-fired power plant before it was shuttered a decade ago, researchers found. Babies born in the southwestern Tongliang county just before the plant was shut in 2004 had significantly lower levels of a protein crucial to brain development in their cord blood than those conceived later, a March 19 report in the Plos One journal said. They also had poorer learning and memory skills when tested at age two, the study by Columbia University and Chongqing Medical University found.